Speaker Hum ,Buzz & Hiss

Ok for the last few years i’ve really struggled with hum from my monitor speakers.
It was much worse on my windows machine and it’s much better now I have an iMac.

Having said that I just don’t understand whats going on.
When I first fire up my speakers everything is silent and lovely!

If I have the speakers on (30 minutes-1 hour-2 hours-all day) i’ll get a gradual speaker hum buzz & hiss.
I don’t get any of the electrical interference, like squeaking and computer talk I used to get on my windows machine which is great.
It’s just a clean “buzzzzzzzzzzzz” sound that overtime suddenly becomes the loudest thing around my desk space.

the interesting thing is that if I turn the speakers off for a good amount of time,maybe half and hour I can then turn them back on ,and for a short amount of time not get the buzzing.

I just wondered if anyone knew how to perhaps eradicate the noise or could explain the science of whats going on and why the noise is there after a short period of time but not when I turn them on initially.

My setup is as follows.
KRK Rokit RP6 , both set to about -20db gain, both plugged into a electrical extension that is designed to eliminate electrical noise.

IMac late 2012 (top spec)

Steinberg CI2+ audio interface

Do both speakers produce this same buzz after the same amount of time and both equally loud?
If you remove the Audio-In cable, do they still develop the buzz?
What happens if you replace the Power Bar with another (even if it’s not a special noise eliminating type)?

Both speakers yes, almost equal but the speaker in the corner (left) is about 20% louder I would say (possibly the corner effect)

Noise is not effected in anyway with the type of cable (TRS-XLR or TRS-TRS) plugged in or not

Type of extension isn’t an issue and has little effect if any, i’ve tried many different ones.

I did have success in the past plugging the speakers into a different power socket in my room.This was when I was using a windows PC and was get screeching noises and computer gibberish through the speakers. I havn’t had anything remotely like that since I bought the iMac

I don’t suppose to alot of people it’s out of the ordinary but I can’t figure out if it’s perhaps the build up of heat for example, or just a build up of interference that somehow needs to be grounded off, I don’t know.

Sounds likely to be a component in the Monitor amps changing over time and temperature. Try to isolate them i.e. remove them both to another room and power them up with no input - let them warm up and check for the noise again try and compare the noise from each with the other in terms of ‘sameness’.
If it were just a poor component, I wouldn’t expect it to be the same in both. That both monitors seem to display the same behaviour, I’d begin thinking this is a poor amplifier design.
How old are these Monitors? Have they been driven hard in previous use?
Have you tried physically grounding their (amp) chassis to a bonafide ground?

Anyone else using KRK Rokits having similar issues (or not) care to join in?

So looking around on the internet at this issue it seems there is or potentially an issue with the transformers that create this noise.
I can almost live with it, its not that bad in reality. i’m just super sensitive to it, I love silence :slight_smile:

I would ask though, am I correct to expect whisper quiet , almost completely quiet, until you put your ear right up to the cone monitor speakers?

My M1’s are pretty lower bracket, and they produce a bit of hiss of themselves (even with signal cable unattached). Nothing you notice while you’re working, but if it’s silent and the computer is off, you’ll hear it.

Not sure about your context here, but notwithstanding the KRK monitors, I would say yes, you should expect whisper quiet with the monitors at least a meter away

whisper quiet = inaudible?

Inaudible was not mentioned.
A whisper can be rather subjective depending upon the sensitivity of the person involved - technically though, 30 - 40 dBs typically covers the levels we’re talking about.

Ok, in that case I would consider my own speakers whisper quiet :wink:.

In regards to the description in your earlier post, so would I. :slight_smile:
The important point is whether it is obtrusive, and whether it will affect the mix!
If the answer to either of the above is yes, then it’s too loud.